Add water, pasta, seasonings, and unsalted butter to the Instant Pot. Mix everything and add unsalted butter on top.
Cover the Instant Pot with its lid and set it to manual high pressure for 4 minutes, following the manufacturer’s instructions.
After the cooking cycle is complete, release the pressure quickly (for safety, I recommend using an oven mitt or kitchen towel to flip the valve and release pressure). Once it’s safe to open, carefully unlock and remove the lid.
Set the instant pot to the sauté setting, add the evaporated milk, and stir.
Then, gradually add 1 cup of cheese at a time, stirring after each addition. Turn off the instant pot. The mac and cheese is done!
If you want to go an extra step, distribute the mac and cheese into individual baking dishes
Add a combination of breadcrumbs and parmesan cheese, and bake at 400 degrees F for 10 minutes.